Memory Card and SIMM Voltages
S1   59F4433
U1 59F4436
S1.5 81F8926
S3.1 00G2208
S3.2 32G1022
S3.3 32G1866
S4.5 52G4801 / 88G3680
S5.0 12H1331
S6   93H5994

Rick Ekblaw opines:
  It would appear that U1 manages the 4 SIMMs on the right and U3 manages the 4 SIMMs on the left, and U2 must be the "memory bus" controller.

S1 59F4433 / 59F4431 (8 SIMM per card)
An SD1 controller has memory controllers  22F9434ESD and 42F6531ESD. 
NOTE: S1 not compatible with S3.1 or higher.
3xx - 320, 32E, 32H
5xx - 520, 52H, 530
7xx - 730, 740
9xx - 930
1MB      59F4581
2MB      59F4582

U1 59F4436 (8 SIMM per card)
NOTE: Not compatible with any other memory.
5xx - 540 ONLY

S1.5 / HD1 81F8926 / 81F8924 (8 SIMM per card) 

U1,3 37F5699ESD
U2   63F7984ESD

3xx - 320, 32E, 32H
5xx - 520, 52H, 530
7xx - 730
9xx - 930
 
 

An HD1 controller has memory controllers 37F5699ESD and 63F7984ESD
NOTE: S1.5 not compatible with S3.1 or higher.
4MB      70F9973 1Mx40,4MB
8MB      70F9976 2Mx40,8MB, 80NS, E

S3.1 00G2208 / 00G2205  (8 SIMM per card) Thanks to Rick Ekblaw
U1,3 63F7862
U2 82F6767

3xx - 340, 350
5xx - 53H, 550
9xx - 950
 
 
 

1MB      59F4581  256Kx40,1MB
2MB      59F4582  512Kx40,2MB
4MB      70F9973  1Mx40, 4MB
8MB      70F9976  2Mx40, 8MB, 80NS, E

S3.2 32G1022 / 32G0101 (8 SIMM per card)
3xx - 340, 350
5xx - 53H, 550, 560
9xx - 950
1MB      59F4581  256Kx40,1MB
2MB      59F4582  512Kx40,2MB
4MB      70F9973  1Mx40, 4MB
8MB      70F9976  2Mx40, 8MB, 80NS, E

S3.3 32G1866 / 32G1846 (8 SIMM per card) 
3xx - 340, 350, 355, 360, 36T, 365, 370, 37T, 375
5xx - 53H, 550, 55L, 560, 570, 580, 58F
7xx - 770, 771
9xx - 950, 970, 97B, 980, 98B
 1MB     59F4581  256Kx40,1MB
 2MB     59F4582  512Kx40,2MB
 4MB     70F9973  1Mx40, 4MB
 8MB     70F9976  2Mx40, 8MB, 80NS, E
16MB     43G1796  4Mx40, 16MB, 60NS, E

3.x Cards used in 4.x Systems
      You can physically install an S3.x card in 3AT / 3BT / 3CT  / 380 / 390 / 39H systems.  Even though they officially support S4.5 memory, or greater, on these systems, there is a potential for someone to put S3.x in.  The S3.3 cards have been installed in several instances.  They can possibly result in random checkstops causing a reboot of the machine.  Another symptom  is that you may get a 15% INCREASE in processing speed with S3.x memory.  Although this is good (from a speed related viewpoint), it is unstable (and unsupported).
    The deskside (7013) and rack (7015) models that require memory cards at S4.5 or higher, have a physical interlock in their design to prevent plugging in lower level cards, but the desktops (7012) do not.

S4.5 52G4801 / 88G3680 (S4.6 same FRUs and memory capacity) Thanks to Rick Ekblaw
U1,3 50G6861 
U2  50G6858 
3xx - 340, 350, 355, 360, 36T, 365, 370, 37T, 375
5xx - 53H, 550, 55L, 560, 570, 580, 58F, 58H, 590
7xx - 770, 771
9xx - 950, 970, 97B, 980, 98B, 990
NOTE: S4.5 / S4.6 Downward compatible except with S1 / S1.5 and U1
 1MB     59F4581  256Kx40,1MB
 2MB     59F4582  512Kx40,2MB
 4MB     70F9973  1Mx40,4MB
 8MB     70F9976  2Mx40, 8MB, 80NS, E
16MB     43G1796  4Mx40, 16MB, 60NS, E
32MB     65G6452  8Mx40, 16MB, 60NS, E (88G3680 only?)P/N 64G2074

Function of Resistor Explained
   The S4.5 and S4.6 memory cards support 2 different FRU number simms that are equivalent.
        4mb simm:  p/n70f9973 = p/n12h1677
        8mb simm:  p/n70f9976 = p/n12h1678
       16mb simm:  p/n43g1796 = p/n12h1679
       32mb simm:  p/n39h8312 = p/n12h1680
 NOTE:  The FRU p/n12h16XX simms were developed with a resistor on the simm for the older S4.5 noise problem.

39H Limits
   The problem of LED 888/103 145/912 on boot at minimum config with the memory card plugged in and the 8 simms installed on the CPU of the 39H, will occur if the simm FRUs p/n12h16XX numbers are installed on the CPU.

   NOTE:  The base card and CPU must both be fully populated with  the same size simms. The FRU p/n12h16XX simms were developed with a resistor on the simm for the older S4.5 noise problem.  They were not approved for installation on CPUs that support simm modules.
 

S5.0  12H1331  / 12H1325  (8 SIMM per card)  Thanks to Rick Ekblaw

U1,3 50G6861
U2 26H4374

5xx - 591, 595
 
 
 
 

 4MB     39H8924 
 8MB     39H8925 
16MB     43G1796 
32MB     39H8312

S6 93H5994/ 93H5993 (8 SIMM per card)

U1,3 50G6861
U2 88H2860

3xx - 397, 39F
9076 - 160MHz Thin Node
 
 
 
 

 4MB    39H8924   1Mx40, 4MB, 60NS, E
 8MB    39H8925   2Mx40, 8MB, 60NS, E
16MB    43G1796   4Mx40, 16MB, 60NS, E
32MB    39H8312   8Mx40, 32MB, 60NS, E

Memory Card Capacities
 Card Type      FRU #       Max per card
------------   -------     -----
SD1    (S1)    59F4433      32Mb
HD1    (S1.5)  81F8926      64Mb
HD3    (S3)    32G1022     64Mb
       (S3.1)  00G2208      64MB
       (S3.2)  32G1022      64MB
HD3.3  (S3.3)  32G1866     128Mb
       (S4.5)  52G4801     256MB
               88G3680
       (S4.6)  52G4801     Typo?
       (S5.0)  12H1331     256MB
       (S6)    93H5994     256MB
NOTE: It may be that some systems do not support larger SIMMs (ex. 32MB) so the max per card may vary.

Memory Card and SIMM Voltage
  Card           Card v  SIMM v Speed 
SD1 / S1           5.0v  5.0v   80-ns 1mbit
HD1 / S1.5         5.0v  5.0v   80-ns 4mbit
HD2 / U1 (U1???)   3.6v  5.0v   80-ns 4mbit
                   3.6v  5.0v   85-ns 2mbit
HD3 / SD3          3.6v  5.0v   80-ns 4mbit
HD3.3 / SD3.3      3.6v  5.0v   60-ns 16mbit
HD4                3.6v  5.0v   60-ns 16mbit